Regioselectivity of Intramolecular Rhodium-Catalyzed C-H Insertion Reactions of α-Aryl-α-diazocarboxylates: Influence of the Aryl Substituent

被引:11
作者
Wamser, Maximilian [1 ,2 ,3 ]
Bach, Thorsten [1 ,2 ]
机构
[1] Tech Univ Munich, Dept Chem, D-85747 Garching, Germany
[2] Tech Univ Munich, Catalysis Res Ctr CRC, D-85747 Garching, Germany
[3] Tech Univ Munich, WACKER Inst Siliciumchem, D-85747 Garching, Germany
关键词
carbene complexes; diastereoselectivity; insertion; lactones; regioselectivity; rhodium; ring closure; GAMMA-BUTYROLACTONES; CARBENE INSERTION; ALDEHYDES; LACTONE; ROUTE; ACID;
D O I
10.1055/s-0033-1341062
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
It was found that alpha-aryl-alpha-diazocarboxylates react with variable regioselectivity in intramolecular rhodium-catalyzed C-H insertion reactions. 3-(Trialkoxysilyl)propyl esters underwent a clean cis-gamma-lactone formation (62-69%) if the aryl rest was a phenyl group while the analogous alpha-(2-bromophenyl)-alpha-diazocarboxylates produced the respective beta-lactones. In general beta-lactone formation was shown to be the only detectable C-H insertion pathway for the latter substrate class irrespective of the ester substituent. The beta-lactone products (eight examples) were obtained in yields of 41-68% with a diastereomeric ratio (dr) of 75:25 to 96:4 in favor of the trans diastereoisomer. The 2-bromo substituent could be displaced by an aryl group in a subsequent Suzuki cross-coupling reaction.
引用
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页码:1081 / 1084
页数:4
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